FROM MICROWAVE ANISOTROPIES TO COSMOLOGY

Fluctuations in the temperature of the cosmic microwave background hav e now been detected over a wide range of angular scales, and a consist ent picture seems to be emerging. This article describes some of the i mplications for cosmology. Analysis of all of the published detections suggests the existence of a peak on degree scales with a height 2.4 t o 10 (90 percent confidence level) times the amplitude of the power sp ectrum at large angular scales. This result confirms an early predicti on, implies that the universe did in fact recombine, and limits theori es of structure formation. Illustrative examples show how comparison o f the microwave background data and the targe-scale structure data wil l be a potentially powerful means of answering fundamental questions a bout the universe.